Laundky souking composition



June 10, 1947.

L. R. BACON LAUNDRY SOURING COMPOS ITION Filed July 2, 1941 IRON STAIN REMOVAL CAPACITIES OF SODIUM SILICO FLUOR|DE,SODIUM ACID FLUOR IDE AND SODIUM ACID SULPHATE MIXTURES WITH IO"/o SODIUM TETRAPHOS PHATE ADDED.

PERCENT IRON 'STAIN REMOVAL RATE OF IRON STAIN REMOVAL FIGLI FIGLZ TIME INVENTOR.

LESLIE R.BACON Mfw JQW,

ATTORNEYS Patented June 10, 1947 LAUNDRY SOURING COMPOSITION Leslie R. Bacon, Wyandotte, Mich., assigner, by mesne assignments, to Wyandotte Chemicals Corporation, Wyandotte, Mich., a corporation of Michigan Application July 2, 1941, Serial No. 400,873

4 Claims.

'I'he present invention relates to a composition of material and a method for treating textiles which, during the course of previous processing, have become subjected to the action of alkali chemical compounds, and as a result thereof, generally retain residues of such alkaline compounds, such as encountered in the textile dyeing, bleaching and washing arts, It is, of course, necessary to remove such alkaline residues from the textile fabric, either prior to subsequent processing treatment or in order to preserve the strength, quality and durability of the finished, treated fabric.

The present invention is particularly adapted for use in connection with the washing and cleansing of cloth goods and textile fabrics. In customary laundry operations, the goods or fabrics are subjected to alkali compounds, such as involved in washing or bleeching treatments, or both, in which alkali metal soaps, alkali metal salts acting as soap builders or water-conditioning agents and alkaline bleaching compounds may be employed in various ways well understood in the art. It is highly desirable to remove such alkaline materials from the goods or fabrics since otherwise the strength and color of the fabric may be affected, and subsequent laundry operations, such as bluing and starching, are in general less satisfactorily performed in the presence of alkali. Mere rinsing is not sufficient to remove alkaline materials from the goods or fabrics.

It has, therefore, been common practice to subject the fabrics to an acidulating treatment, which is customarily known in the laundry art as souring and the composition employed in such treatment is known as a laundry sour." The chief purpose of a laundry sour is to neutralize residual alkaline materials to which the fabrics have been previously subjected in the laundry operations. Iron or rust stains in the goods or fabrics, not being removed by previous Washing or bleaching operations by treatment with alkaline materials, must also be removed by treatment with the acidulating composition.

Many acidic compositions, previously known and used for such purposes are likely to have a deteriorating or weakening effect upon the cloth or fabric, which, in turn, might be as greatly detrimental as the presence of the alkaline material therein. Accordingly, it is highly desirable that a laundry sour composition, while possessing the required acidic properties, be capable of complete safety of use in fabric treatment, Without any deteriorating o1 detrimental effect upon fabric strength and fabric life, and without the necessity of technically rened control over concentrations, temperatures and other variables encountered in general laundry practice.

While the use of hydrochloric, sulfuric, phosphoric, and other strong acids for neutralizing alkali is known in the textile industry where technical control can be exercised, the use of these acids is not generally practicable in the laundry. Acidic materials which have heretofore been customarily used as laundry sour compositions, either as pure compounds or mixtures thereof, have comprised acids, such as formic, acetic, oxalic, tartaric and citric acids; fluorine compounds, such as sodium zinc, or ammonium silicofiuorides and sodium or ammonium biuorides; and sodium acid sulfate. These compounds or mixtures thereof, of course, possess the necessary capacity for neutralization of alkali, but are, nevertheless, deficient in one or more respects with regard to the other highly desirable and important functions of iron stain removal and safety to fabric strength.

I have discovered that by the addition of polyphosphates to such previously known and used acidic materials or mixtures thereof, that the previously encountered disadvantages and detrimental effects are overcome. The polyphosphates which I have found to be satisfactory for the purpose of my invention comprise the alkali metal or ammonium tetraphosphates and hexametaphosphates and the so-called tri-polyphosphates and triphosphatesf The precise-constitution of many such tripolyphosphates and tri-phosphates is neither agreed upon nor fully understood at this time. The polyphosphates which I desire to embrace in this disclosure are characterized by their ability to sequester ions such as of calcium, magnesium, iron, lead, copper, zinc and the like into more or less stable soluble complexes with the polyphosphate radical or aggregate, Without regard to mode of preparation of the polyphosphate or structure, and not including pyrophcsphate, characterized by the radical P201. It is, therefore, the phosphate compounds at last defined, which are intended to be covered by the term polyphosphates, as employed in the present description and appended claims.

Such polyphosphates, according to the principle of my invention, are added to the acidic compounds or mixtures thereof in an amount of 1% to 25% of the resulting laundry sour composition, which composition, in addition to having the required alkali neutralization capacity, has an unusual and unexpected ability to remove iron and rust stains, while, at the same time, counteracting the fabric strength deteriorating effect of any of the acidic materials present.

The laundry sour composition of my invention also possesses the advantage of improving the subsequent action of the bluing treatment to which the goods or fabrics are subjected. Laundry blues, usually consisting of aniline dyes, are used for the purpose of imparting whiteness to the finished laundry work. My present laundry sour composition possesses the ability of effecting the uniform and even distribution of the bluing throughout the fabric, without the appearance of blue colored spots. This function of distributing bluing material in the fabric is commonly termed "leveling or fixing of the blue.

The laundry sour composition of my invention also results in an improved solubility and rate of solution so that no difficulty is encountered in making up the necessary laundry souring bath. Thus, my laundry souring composition may be used in either the wet or dry form, viz., in the preparation of a stock solution, portions of which are drawn oil from time to time and introduced to the laundry wheel, or by direct addition in the dry or solid form to water which is already present in the laundry wheel.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail one method and composition exemplifying my invention, such disclosed procedure and composition constituting, however, but one of various applications of the principle of my invention.

In said annexed drawing- Fig. 1 is a dia-gram illustrating the improved iron stain removal capacities of compositions embodying the principle of my invention; and Fig. 2 is a diagram illustrating the rate of iron stain removal of compositions of my invention as compared to the rate of iron stain removal of previously used compositions.

Acidic compounds which have been most frequently used heretofore in laundry sour compositions because of their iron stain removal capacity, in addition to their ability to neutralize alkalies, comprise acid-forming fluorine compounds, such as sodium silicoiluoride, NazSiFr., sodium bifluoride, NaHFz, ammonium silicofiuoride, (NHqlzSiFs, sodium bisulphate and oxalic acid. I have found that by the addition of 1 to a `a-pirlyp-hesphate...ttinsuch. lOllfllDGundS. such as sodium, potassium, or ammonium, Vtetra'- phosphate, (e. g., NaeP4O13), hexametaphosphate (e. g., (NaPO3)G), tri-polyphosphate or tri-phosphate, that the ability of the resultant composition to remove iron or rust stain from goods or fabrics is greatly increased. In fact, such increase is of a synergistic nature. That is to say, the total capacity of the compositions with the polyphosphate addition, to remove iron or rust stain, is greater than the arithmetic sum of the capacities of the individual ingredients. This result is particularly unexpected when it is considered that the polyphosphates used alone show little or no iron or rust stain removal capacity.

Iron stain removal capacity of a laundry sour composition is customarily measured by the optical reflectivity test. Thus, for example, in applying such test to my invention, sample pieces of fabric are first stained by being treated with a standard iron stain solution and their reflectivity measured on a Hunter reectometer. The fabric pieces, after such standard iron stain or soiling, are then placed in 100 ml. of an .05% solution of the laundry sour composition which is to be tested and Washed for 10 minutes in a standard laboratory washing apparatus known as a Launder-Ometer. (Model LI-ID-EF, manufactured by Atlas Electric Devices Co., Chicago, Ill.) Each small piece of fabric, after being washed for l0 minutes in the Launder-Ometer at a temperature of F., is then rinsed, extracted and dried in a laundry tumbler. Each set of standardly soiled fabric pieces are washed according to this procedure for 5 times and then ironed. The reflectivity of the standardly soiled or stained pieces, so treated, is measured with a Hunter reflectometer, using the blue filter, and the iron stain removal capacity of the tested laundry sour composition is taken to be the percentage regain of the reflectivity lost from the original cloth due to standard soiling.

The results of such tests bear out the unusual advantages of the laundry sour compositions of my invention. For example, using solutions of 0.05% strength, the iron stain removal capacity of sodium silicofluoride has been determined to be 34% (when measured by the above described optical reflectivity test), that of sodium bisulphate 6% and that of sodium tetraphosphate 0.0%. Amixture of 70% of sodium silicofluoride, 20% of sodium bisulphate and 10% sodium tetraphosphate, resulted in an iron stain removal capacity of'53%, or an increase of 55% over the iron stain removal capacity of the most superior stain removing ingredient (sodium silicofluoride) alone, of the mixture. It is to be made clear, however, that the optical reflectivity values cited in this disclosure while absolute for the standard soiled fabric herein used, would be comparable only in a relative sense with data obtained by the use of a differently stained standardized fabric.

It has also been determined that laundry sour compositions of the present invention may be employed with complete safety as to the fabric strength. The eilect of laundry sour compositions upon fabric strength is determined by a bursting strength loss test.

The procedure for this test is as follows:

Sample pieces of pre-shrunk, uniform cotton sheeting are wet with water, treated in a wash wheel with a 1/10 of 1% solution of the laundry sour solution for l0 minutes, then run through a squeeze roll and dried at 300 F. for 10 minutes. After drying, the cycle of treatment is repeated 5 times. The bursting strength of the treated pieces is then determined by measurement on a Mullen tester and the percent of bursting strength loss determined by the percentage proportion of the reading from a treated sample piece of fabric to that of an untreated one. Thus, for example, sample pieces of fabric tested by the foregoing procedure show a bursting strength loss of 44% when treated with sodium bisulphate and '72% when treated with oxalic acid. The above-mentioned exemplary composition of my invention (70% sodium silicofluoride, 10% sodium tetraphosphate and 20% sodium bisulphate) showed no bursting strength loss of the treated fabric. Thus, the deteriorating effect of the sodium bisulphate upon the fabric strength was completely counteracted.

If oxalic acid is substituted for a portion of the sodium bisulphate in this exemplary composition, the oxalic acid having a still greater deteriorating effect upon the fabric strength, it is nevertheless found that such greater deteriorating effect is overcome and no bursting strength loss occurs.

For example, a composition of '70% sodium silicofluoride, 10% sodium tetraphosphate, 12% sodium bisulphate and 8% oxalic acid, results in no bursting strength loss of the fabric treated, with an iron stain removal capacity of 64%.

The following are other specific examples of laundry sour compositions, made according to the principle of my invention and in which the improved properties thereof are noted:

Example 1 Ninety grams of sodium silicofluoride were mixed with ten grams of sodium tetraphosphate. This composition removed 40 per cent of the iron stain, While sodium silicouoride alone removed 34 per cent of the iron stain.

Erample 2 Eighty grams of sodium silicofluoride were mixed with 10 grams of sodium tetraphophate and 10 grams oi sodium bisulphate. This composition removed 47 per cent of iron stain.

Eample 3 Seventy-ve grams of sodium silicofluoride were mixed with l grams of sodium tetraphosphate and 15 grams of sodium bisulphate. This composition removed 50 per cent ofthe iron stain.

Example 4 Sixty-five grams of sodium silicouoride were mixed with 10 grams oi sodium tetraphosphate and 25 grams of sodium bisulphate. This composition removed 47 per cent of the iron stain.

Example 5 Sixty grams of sodium silicofiuoride were mixed with grams of sodium tetraphosphate and 30 grams of sodium bisulphate. This composition removed 42 per cent of the iron stain.

Example 6 Eighty grams of sodium bifluoride were mixed with 10 grams of sodium tetraphosphate and 10 grams of sodium bisulphate. This composition removed 60 per cent of the iron stain. Sodium biuoride alone removed 50 per cent of the iron stain.

Example 7 Seventy-live grams of sodium bifluoride were mixed with 10 grams of sodium tetraphosphate and grams of sodium bisulphate. This composition removed 59 per cent of the iron stain.

Example 8 Seventy grams of sodium biluoride were mixed with 10 grams of sodium tetraphosphate and 20 grams of sodium bisulphate. This composition removed 60 per cent of the iron stain and gave no bursting strength loss. This composition had a solubility of 5 per cent compared to 4.1 per cent for sodium bifiuoride. By reason of its good solubility it may be prepared and used either in the dry or liquid form. The addition of sodium bisulphate considerably decreased the cost, while the addition of sodium tetraphosphate increased the ability to remove iron stains.

Example 9 Sixty-ve grams of sodium biuoride were mixed with 10 grams of sodium tetraphosphate and grams of sodium bisulphate. This composition removed 56 per cent of the iron stain.

Example 10 Sixty grams of sodium bifluoride were mixed with 10 grams of sodium tetraphosphate and 30 grams of sodium bisulphate. This composition removed 55 per cent of the iron stain.

Example 11 Seventy grams of sodium biuoride were mixed with 10 grams of sodium tetraphosphate, 12 grams of sodium bisulphate and 8 grams of oxalic acid. This mixture removed 53 per cent of the iron stain.

Example 12 Seventy grams of sodium silicoiiuoride were mixed with 10 grams of sodium hexametaphosphate and 20 grams of sodium bisulphate. This mixture removed 44 per cent of the iron stain.

Example 13 Seventy grams of sodium silicofluoride were mixed with 10 grams of sodium hexametaphosphate, 12 grams of sodium bisulphate and 8 grams of oxalic acid. This mixture removed 52 per cent of the iron stainl Example 14 Eighty grams of ammonium silicouoride were mixed with 10 grams of sodium tetraphosphate and l0 grams of sodium bisulphate. This mixture removed 48 per cent of the iron stain, while ammonium silicofluoride alone removed 44 per cent. This composition gave no bursting strength loss.

Example 15 Seventy grams of ammonium silicofluoride were mixed with 10 grams of sodium tetraphosphate and 20 grams of sodium bisulphate. This mixture removed 49 per cent of the iron stain.

Fig. 1 further exemplies the unusual improvement in iron stain removal capacity of the compositions of my invention. The horizontal dotted lines in the diagram of this figure show the iron stain removal capacities of the several ingredients alone. The sodium tetraphosphate addition has no iron stain removal capacity. The solid line curves show the iron stain removal capacities of the mixtures in which the sodium bifluoride and sodium bisulphate ingredients in one case have been varied over a 30% range (sodium biuoride, 60 to 90%, and sodium bisulphate up to 30%). The upper curve represents the percentage of iron stain removal, as measured by the previously described optical reflectivity test of such mixtures with the 10% sodium tetraphosphate addition. It will be seen that all portions of this curve lie well above the per cent of iron stain removal possible by sodium bifluoride alone, which is the ingredient possessing the most superior stain removing capacity of any of the ingredients in the mixture. Similarly, it will be found that the second curve, representing mixtures of sodium Silico-fluoride, sodium bisulphate and sodium tetraphosphate, lies above the capacity of the most superior stain removing ingredient, sodium silicouoride.

The rate of iron stain removal is also a very important factor in the action of a laundry souring composition. The rate of iron stain removal is determined by plotting the optical reflectivity percentage readings against the time of exposure of the sample fabric pieces to the laundry souring compositions.

Fig. 2 illustrates the distinctive difference in the rate of iron stain removal of such compositions in which the polyphosphate addition of my invention has been incorporated as compared to those in which it is absent. Thus, the dotted line curves No. 4 and 1 in Fig. 2 show the progress of iron stain removal by sodium 'biuoride and sodium silicoiiuoride, respectively. The solid line curve No. 2 represents a composition comprising 90% sodium silicoiiuoride and 10% sodium tetraphosphate. The solid line curve No. 3 represents a composition comprising '70% sodium silicoiiuoride, 20% sodium bisulphate and 10% sodium tetraphosphate. The solid line curve No. 5 represents a composition comprising 70% sodium acid fluoride, sodium bisulphate, and 10% sodlum tetraphosphate. Thus, the solid line curves 2, 3 and 5 represent compositions of the same constituency as may be located in Fig. 1. The curve 2 differs from the curve I, for example, in that 10% of the straight sodium silicofluoride has been replace by the same amount of sodium tetraphosphate.

Interpreting the curves of Fig. 2, it will be seen that the simple uorides alone, viz., the sodium bifiuoride and the sodium silicofluoride (curves 4 and 1) show a high rate of soil removal for a short period, but that this rate soon approaches a limiting value; whereas, in the case of the compositions of the present invention (curves 2, 3 and 5), even though the initial rate of iron stain removal is slower, a higher rate is soon established, which advantage is maintained for a long and indefinite period of time, with the net result that the laundry sour compositions of my invention soon achieve a higher degree of soil removal and remain still active in removing iron and rust -stains, and at a relatively high rate, while those compositions not embodying the polyphosphate addition have exhausted their stain removal capacity to a major degree.

In addition to the above-described results of the compositions of the present invention with regard to iron stain removal, counteracting of fabric strength deterioration and sustained maximum rate of iron stain removal, it is to be pointed out that improved leveling and xing of the blue, relatively rapid rate of solution, adequate solubility and removal of insoluble soaps are additional attributes and advantages found to be present.

The composition of the present invention is, `"`ofponrsermadeaup.intopmouringsolution or bath to which the textile goods and fabrics are subjected after the usual prior operations of washing, bleaching and rinsing. A sufficient amount of my sour composition is added to the bath to bring it to the desired degree of acidity, which, of course, varies with the type of laundry work. Each ingredient of my composition may be added separately in the make-up of the solution, if desired.

Thus, after the laundering operations of washing, bleaching and rinsing, the polyphosphate salts within the scope of my invention may be added to the bath, followed by the addition of the proper amount of acidic or acidifying compounds or mixtures thereof. On the other hand, the polyphosphate salts and the acidifying compounds may be previously mixed together in solid or dry form and such mixture then placed in the solution.

It should also be pointed out that while many of the ammonium and alkali-metal salts of the polyphosphates are at this time relatively unknown, not being isolated or in existence as salts per se, they may still exist in souring baths in soluble form as a consequence of reactions of which the following are illustrative:

Thus, the existence of eithel` ammonium polyphosphates or mixed sodium-ammonium polyphosphates in solution is entirely reasonable. Specific disclosures of this class have been made in Examples 14 and 15, hereinabove, and of course are intended to be included within the scope of my invention as defined in the appended claims.

Although in the foregoing description, I have explained the nature of my invention in detail in connection with the art of washing and cleans ing of textile goods and fabrics, it will be appreciated by those skilled in the art that the principle of my invention is also applicable to related textile treating processes wherein it is found desirable and necessary to neutralize alkaline residues associated with the textile materials.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the composition and method herein disclosed, provided the ingredients or steps stated by any of the following claims or the equivalent of such stated ingredients or steps be employed.

I, therefore, particularly point out and distinctly claim as my invention:

l. A laundry souring composition, comprising by weight approximately 10% sodium tetraphos phate, not over 30% sodium bisulphate and 60 to sodium silicoiiuoride.

2. A laundry souring composition, comprising by weight approximately 10% sodium tetraphosphate, approximately 70% sodium biluoride and the balance selected from the group consisting of sodium bisulphate and oxalic acid.

3. A laundry souring composition having over a 50% iron stain removal capacity as measured by the optical reflectivity test, comprising by weight approximately 10% sodium tetraphosphate, not over 30% sodium bisulphate and 60 to 90% sodium biuoride.

4. A laundry souring composition comprising, by weight, approximately 10% sodium tetraphosphate, approximately '70% sodium silicofluoride and approximately 20% sodium bisulphate.

LESLIE R. BACON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,086,867 Hall July 13, 1937 2,092,913 Fiske Sept. 14, 1937 1,434,551 McAdam et al. Nov. '7, 1922 FOREIGN PATENTS Number Country Date 435,710 Great Britain Sept. 26, 1935 449,275 Great Britain June 24, 1936 OTHER REFERENCES Applications of Sodium Metaphosphate, article by Munter et al. Reprint from American Dyestuff Reporter, issue of January 28, 1935.

Washing, Cleaning and Polishing Materials, Bureau of Standards Circular C 424, 1939. 

